1. Field of the Invention
The present invention relates to a hybrid integrated circuit device, and more particularly to a hybrid integrated circuit device in which the bonding with the fine metal wire can be reduced and the number of assembling steps diminished.
2. Description of the Related Art
Conventionally, a hybrid integrated circuit device to be placed in the electronic equipment is formed with a conductive pattern on a printed circuit board, a ceramic substrate, or a metallic board, in which the active elements such as an LSI or a discrete TR and the passive elements such as a chip condenser, a chip resistor or a coil are mounted on the conductive pattern. And the conductive pattern and said elements are electrically connected to realize a circuit with predetermined functions.
One example of the circuit is shown in FIG. 19. This circuit is an audio circuit, with those elements mounted as shown in FIG. 20.
In FIG. 20, a mounting board 1 with at least its surface insulated is shown by the outermost rectangular line. And on this mounting board 1, a conductive pattern 2 made of Cu is formed. This conductive pattern 2 is made up of an outside lead-out electrode 2A, an interconnect 2B, a die pad 2C, a bonding pad 2D, and an electrode 4 for securing a passive element 3.
The die pad 2C has a TR, a diode, a composite element or an LSI fixed by solder in a bare chip form. And the electrode on the fixed chip and the bonding pad 2D are electrically connected via the fine metal wires 5A, 5B, 5C. This fine metal wire is typically classified into those for a small signal and a large signal, a fine metal wire of 20 to 80 μmφ being used for small signal purpose. Here, the Au wire 5A or Al wire of about 40 μmφ is employed. Also, for large signal purpose, the Au wire or Al wire of about 100 to 300 μmφ is employed. In particular, the wire diameter for large signal is great, and in view of the costs, the Al wire 5B of 150 μmφ or the Al wire 5C of 300 μmφ is selected.
A power TR 6 for passing a large current is fixed to a heat sink 7 on the die pad 2C to prevent temperature rise of the chip.
And the interconnect 2B for connecting the outside lead-out electrode 2A, the die pad 2C, the bonding pad 2D, and the electrode 4 extends over the board to make a circuit. Also, in the case where the interconnects cross each other owing to the chip position or the way of interconnecting, the jumping wires 8A, 8B are employed.
As will be apparent from FIG. 20, a chip conductor, a chip resistor, a small signal TR chip, a large signal TR chip, a diode, and an LSI are employed, and fixed by the brazing material. And the semiconductor element such as a TR chip is electrically connected using a fine metal wire. This fine metal wire is classified into a plurality of sorts depending on the current capacity. There are a great number of sorts for the fine metal wire. As can be seen from this, the fixing of chip or connection of fine metal wire brought about the problem that the assembling process is significantly complex, resulting in the increased costs.
Lately, the chips having a chip size of as small as 0.45×0.5 mm, 0.25 mm in thickness with the low unit price have been put on the market. However, if this chip is fixed by solder, the solder is sucked up on the side face of chip, causing a short-circuit, and making it difficult to employ this chip for the hybrid integrated circuit device.
If a package with the semiconductor elements fixed on a lead frame is mounted on a hybrid integrated circuit board, the size of this package is very great, resulting in the problem that the size of the hybrid integrated circuit board is increased.
As described above, even if the hybrid integrated circuit board was employed to cut down the costs, there was the problem that the very small chips could not be mounted, and the assembling process was lengthened to increase the costs.